Abstract

Ni-Cr-W matrix cermet composites were prepared using powder metallurgical technology, and their microstructures, phase compositions, and mechanical properties were determined. Specifically, the tribological performances of the Ni-Cr-W composites were evaluated at a speed of 0.5 mm/s from room temperature to 800 degrees C, and their friction-reducing mechanism was clarified. The results showed that the NiCrW/Al2O3/Ag composite had the highest mechanical strength, with a 94.5 % increase in tensile strength compared to NiCrW/Al2O3. The NiCrW/Al2O3/SrCO3 composite exhibited the best high-temperature tribological performance because the chemical reaction on the friction surface generated new lubricating phases consisting of NiO, WO2, WO3, and Sr2CrO4. These acted synergistically lubricate and anti-wear with the Al2O3, Cr2O3, and NiCr2O4, and formed a continuous glaze layer on the wear surface. Furthermore, the multiple roles of nano-alumina in the obtained composite and its service in friction were discussed.

Keywords Plus：TRIBOLOGICAL PROPERTIES，MECHANICAL-PROPERTIES，NICR-AL2O3 CERMET

Published in TRIBOLOGY INTERNATIONAL，Volume 198；10.1016/j.triboint.2024.109921，OCT 2024